I'm not a fan. I favour people teaching their kids how to properly approach a dog; owners of dogs teaching people how to properly approach their dog.
Of course this leaves out people who don't know or give a hoot about their dog, the ones who leave poop on the ground, let their dog run loose, get pregnant, chase cars and guess what? I don't trust those kinds of people to put a yellow ribbon on a dog that should have one. And I fear for the poor people who think because that dog doesn't have a yellow ribbon it must be ok.
Actually, now that I've written this all out I've just convinced myself it's a bad idea. Does any parent ever tell their kid it's all right to cross the street just because their light is green and not to look first? Nope, because there might always be some dopey driver who misses their red light and hits that kid. Same thing I think.